The split Hopkinson pressure bar （SHPB） testing with diameter 40 mm was used to investigate the dynamic mechanical properties of engineered cementitious composites （ECCs） with different fly ash content. The basic ...The split Hopkinson pressure bar （SHPB） testing with diameter 40 mm was used to investigate the dynamic mechanical properties of engineered cementitious composites （ECCs） with different fly ash content. The basic properties including deformation, energy absorption capacity, strain-stress relationship and failure patterns were discussed. The ECCs showed strain-rate dependency and kept better plastic flow during impact process compared with reactive powder concrete （RPC） and concrete, but the critical compressive strength was lower than that of RPC and concrete. The bridging effect of PVA fiber and addition of fly ash can significantly improve the deformation and energy absorption capacities of ECCs. With the increase of fly ash content in ECCs, the static and dynamic compressive strength lowered and the dynamic increase factor enhanced. Therefore, to meet different engineering needs, the content of fly ash can be an important index to control the static and dynamic mechanical properties of ECCs.展开更多
采用自约束热疲劳试验方法 ,在相同的热处理条件下 ,对比研究了 840 7、4Cr5 Mo Si V1钢的纵横向热疲劳特性 ,观察分析了两种钢的热疲劳裂纹形貌及深度 ,并选择典型试样进行扫描电镜分析 .结果表明 ,840 7钢比4Cr5 Mo Si V1钢的碳化物...采用自约束热疲劳试验方法 ,在相同的热处理条件下 ,对比研究了 840 7、4Cr5 Mo Si V1钢的纵横向热疲劳特性 ,观察分析了两种钢的热疲劳裂纹形貌及深度 ,并选择典型试样进行扫描电镜分析 .结果表明 ,840 7钢比4Cr5 Mo Si V1钢的碳化物颗粒较小 ,而且分布均匀 ,从而表现出较好的热疲劳性能 ;尤其是 4Cr5 Mo Si V1钢的横纵向热疲劳性能差异较 840 7钢大 ,即 840 7钢的各向同性要优于 4Cr5 Mo Si V1钢 ,与两种钢的横纵向冲击韧性的比值相对应 .展开更多
文摘The split Hopkinson pressure bar （SHPB） testing with diameter 40 mm was used to investigate the dynamic mechanical properties of engineered cementitious composites （ECCs） with different fly ash content. The basic properties including deformation, energy absorption capacity, strain-stress relationship and failure patterns were discussed. The ECCs showed strain-rate dependency and kept better plastic flow during impact process compared with reactive powder concrete （RPC） and concrete, but the critical compressive strength was lower than that of RPC and concrete. The bridging effect of PVA fiber and addition of fly ash can significantly improve the deformation and energy absorption capacities of ECCs. With the increase of fly ash content in ECCs, the static and dynamic compressive strength lowered and the dynamic increase factor enhanced. Therefore, to meet different engineering needs, the content of fly ash can be an important index to control the static and dynamic mechanical properties of ECCs.
文摘采用自约束热疲劳试验方法 ,在相同的热处理条件下 ,对比研究了 840 7、4Cr5 Mo Si V1钢的纵横向热疲劳特性 ,观察分析了两种钢的热疲劳裂纹形貌及深度 ,并选择典型试样进行扫描电镜分析 .结果表明 ,840 7钢比4Cr5 Mo Si V1钢的碳化物颗粒较小 ,而且分布均匀 ,从而表现出较好的热疲劳性能 ;尤其是 4Cr5 Mo Si V1钢的横纵向热疲劳性能差异较 840 7钢大 ,即 840 7钢的各向同性要优于 4Cr5 Mo Si V1钢 ,与两种钢的横纵向冲击韧性的比值相对应 .
